Wood ash used as partly sand and/or cement replacement in mortar

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Abstract

Wood ash (WA) is the residue generated during incineration of wood and wood products. The WAs in focus of this work are from incineration of virgin wood. Physical and chemical properties of WA vary significantly depending on many factors related to the wood species and the incineration process, and the present work reports a characterization of three different WAs. Properties of mortar samples with the WAs used as partly cement and/or sand replacement are reported. Compressive strength development and porosity are the mortar properties in focus. The overall aim of the work is to evaluate the influence from the differences in ash characteristics to the properties of the mortar samples. The characteristics of the ashes did vary considerably. For example, one ash had very high loss on ignition (LoI) of 14% compared to 3% for the other ashes. Ash solubility in water ranged from 18% to 28%. Two of the ashes were dry and sampled just after the incineration, whereas one ash had a water content of 15%, because the ash was sprayed with water to avoid dust during ash handling at the incineration plant. Regardless of replacing cement or sand with WAs, the compressive strength decreased compared to a reference without ash, however, the decrease was small for two of the ashes. Using the ash with the high LoI resulted in significantly lower compressive strength compared to the other two ashes. The mortar samples with two of the ashes (with low LoI) had qualities, which were very encouraging in order to use WA as partly cement replacement (<10%). At higher percentages the workability was so low that extra water needed to be added and the results depended on the water:cement ratio rather than the ash mass.
Original languageEnglish
JournalInternational Journal of Sustainable Development and Planning
Volume11
Issue number5
Pages (from-to)781-791
ISSN1743-7601
DOIs
Publication statusPublished - 2016
EventWaste Management 2016: 8th International Conference on Waste Management and the Environment - Valencia, Spain
Duration: 7 Jun 20169 Jun 2016
Conference number: 8

Conference

ConferenceWaste Management 2016
Number8
CountrySpain
CityValencia
Period07/06/201609/06/2016

Keywords

  • Cement replacement
  • Compressive strength
  • Mortar
  • Wood fly ash

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